A CAPTCHA (Completely Automated Public Turing test to tell Computers and Humans Apart) is a method used to determine whether a user is a human or a machine. Here’s how it typically works:
1. **Challenge Generation**: When a user accesses a website that employs a CAPTCHA, the system generates a challenge that is easy for humans to solve but difficult for automated bots. Common types of challenges include:
- **Text-based CAPTCHAs**: Users